Imagine purchasing crypto token X today. It is worth 1 USD. Let’s say it goes up in value to five dollars and you then decide to purchase a bit of crypto token Y with your gains. Now crypto token Y must be thought of as a result and continuation of the now divided value of X, and any fluctuations in the value of this token Y will actually be fluctuations in the value of the now exchanged percentage of token X. Meanwhile, the rest of the original token X, not used to purchase some of token Y, must be accounted for separately. When it comes time to pool your X and Y coins together and purchase that sweet new sweater you’ve been eyeing, you now have to calculate your total profit by tracking the price fluctuations of both coins, and then report that to the tax man.
Is that so?
What if you just convert everything back to X and convert X into fiat and pay your taxes. If you have more of X than you originally had, then just sell whatever extra X you gained and pay capital gains tax assuming you got it for free.
At least Finland will not tax profits in crypto-to-crypto exchanges and will only tax anything at conversion to fiat or goods or services. Crypto-to-crypto exchanges are not tax events at all.